SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c73f9b75d85492f99bfb2d839cb5addf1e45c87a239f45c1b5b854dd233d969b' 
  AND token = 'GLX3+sxnJH0sgyi+g7tlRVg4ArjqF6FY9K/tYavJa6s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}